A. Alpha, Beta-Unsaturated Carbonyl Compounds
An alpha, beta-unsaturated carbonyl compound is a compound having the following chemical formula: EQU R.sub.2 C.dbd.CR--CRO or R.sub.2 C.dbd.CR--CN
where each R is any substituent group.
Alpha, beta-unsaturated carbonyl compounds are described generally in Morrison, R. T. and Boyd, R. N. Organic Chemistry, pp. 865 et seq. (3d Ed. Allyn and Bacon, Inc. 1973). Typical substituent groups include hydrogen and alkyl, aryl, and aralkyl groups. An alpha, beta-unsaturated carbonyl compound is distinguished by the fact that the carbon-carbon double bond is conjugated with the carbon-oxygen double bond or the carbon-nitrogen triple bond. Because of this conjugation, alpha, beta-unsaturated carbonyl compounds possess special chemical properties in addition to the properties of their individual functional groups.
Some of the more commercially important alpha, beta-unsaturated carbonyl compounds are set forth below:
______________________________________ H.sub.2 CC(CH.sub.3)COOCH.sub.3 H.sub.2 CCHCOOCH.sub.2 CH.sub.3 Methyl 2-methyl- Ethyl propenoate propenoate (Ethyl acrylate) (Methyl meth- acrylate) H.sub.2 CCHCN C.sub.6 H.sub.5 CHCHC(O)CH.sub.3 Propenenitrile 4-Phenyl-3-buten-2-one (Acrylonitrile) (Benzalacetone) H.sub.2 CCHCHO H.sub.2 CCHCOOH Propenal Propenoic acid (Acrolein) (Acrylic acid) CH.sub.3 CHCHCHO ##STR1## 2-Butenal cis-Butenedioic anhydride (Crotonaldehyde) (Maleic anhydride) C.sub.6 H.sub.5 CHCHCHO HOOCCHCHCOOH 3-Phenylpropenal Butenedioic acid (Cinnamaldehyde) (Maleic or Fumaric acid) ______________________________________
B. Preparation of Alpha, Beta-Unsaturated Carbonyl Compounds
Although there is no single method for preparing all types of alpha, beta-unsaturated carbonyl compounds, there are methods available for producing certain classes of these compounds. See generally Morrison, R. T. and Boyd, R. N. Organic Chemistry, pp. 865 et seq. (3d Ed. Allyn and Bacon, Inc. 1973). For example, alpha, beta-unsaturated aldehydes and ketones can prepared by dehydrating aldol condensation products; alpha, beta-unsaturated carboxylic acids and esters are prepared by the dehydrohalogenation of alpha-halo acids or esters; and aromatic alpha, beta-unsaturated carboxylic acids are prepared by the Perkin condensation reaction. An example of each of these reactions is shown below.